Calcium metasilicate is known and used as Wollastonite as a filler for dental abrasives, (U.S. Pat. No. 4,038,380) bone implants, automotive parts (WO 9103513, U.S. Pat. Nos. 4,943,603 and 4,871,789), paints (JP 1141964), molded plastics U.S. Pat. No. 3,007,757 bone implants (DDR 268130, 268113, 268114), orthopedic casts (U.S. Pat. No. 4,473,671), acrylic coating for finger nails (U.S. Pat No. 4,626,428) and sealants (U.S. Pat. No. 4,816,509).
The object of the media for cleaning is to dislodge or remove the surface contaminant so as to minimize as much as possible dust formation, to absorb the same possibly within the interstices of the media, and then to release the contaminant from the media into a washing fluid during a cleaning operation. Cleaning of the media allows the media to be re-used and facilitates concentration of the contaminants for efficient disposal in a reduced volume.
Suitable blasting equipment for propulsion of media according to the present invention is described in U.S. patent application Ser. No. 07/376,764, now abandoned filed Jul. 7, 1989 hereby incorporated by reference. The operation of such blasting equipment is facilitated by a product having the characteristics of the preferred embodiment of the invention which greatly enhances its operation. The prescribed characteristics of the media include, but are not limited to, angle of repose, density, tensile strength, particle size, lipophilicity and cost. Clarification of the above terminology with respect to the present invention will become apparent to those skilled in the art with reference to the following detailed description and accompanying drawings.
Materials are also known which are used for cleaning as particulate cleaning agents.
U.S. Pat. No. 4,594,362 to Smith and Murphy concerns a textile cleaning stick yielding shreds which serve to remove soil. Silanes are used to bind the abrasive particles to the foam matrix.
A granulated form of media is described, for instance, in U.S. Pat. No. 4,551,481 to Smith et al in which such media is generally used for the cleaning of rugs or floors. That U.S. Patent is believed to be the most relevant prior art to the preferred embodiment of the present invention. Other particle abrasive system to be used in machinery which propels abrasive against a substantially hard surface to remove or polish the surface are known. See U.S. Pat. Nos. 4,034,769, 3,918,220, 3,912,667, 2,609,347, 2,664,366, 4,537,914 and 4,343,910.
Calcium sulfate is known and used as gypsum in building materials such as wall board. Gypsum has the formula CaSO.sub.4 .times.H.sub.2 O and is used in its hydrated or calcined (non-hydrated) form as a filler for paints and candies, fertilizer, as an additive to soften Portland cements, as a plastic and for making plasterboard and wallboard. Other materials are known to be added to the gypsum as an admixture to form building materials.
This U.S. Pat. No. 4,100,242 to Leach shows addition of polystyrene beads to gypsum. Dixon et al in U.S. Pat. No. 2,862,829 adds animal or vegetable material to gypsum to form a building material. Preformed foam is added to gypsum to produce a light-weight building material, U.S. Pat. No. 2,731,377 to Riddell et al. uses a resin admixed with gypsum for a building material. Also see U.S. Pat. No. 4,229,223 to flake showing addition of a resin foam to gypsum to form a building material.
JP 736 00 22 mixed polyurethane foam with a styrene monomer to react same. This was then mixed with CaSO.sub.4.5H.sub.2 O and water. Thus the polymer is formed first and then mixed with gypsum.
JP 5009624 appears to be primarily a gypsum product as opposed to the invention teaching a reaction product of a water-foamable product, polystyrene and CaSO.sub.4.
A product according to U.S. Pat. No. 4,551,481 was evaluated and found to have too low a dry density to be propelled properly by the intended blasting equipment and, in addition, dusted significantly upon impact. Attempts to improve product performance by the use of various fillers failed. The following is a table of the fillers, silane and the prepolymer contents, by weight, tested.
______________________________________ % Silane No. Filler Tested Content % Prepolymer ______________________________________ 1 FELDSPAR .5-5 5-20 2 GYPSUM .5-5 5-20 3 ATTAPULGITE .5-5 5-20 4 ALUMINUM OXIDE .5-5 5-20 ______________________________________
Each of the above materials was evaluated for flow through suitable blasting equipment and for dusting. The above materials were found unacceptable for the equipment and/or because of dusting and breakdown.
U.S. Pat. No. 4,158,576 to Butz shows sponges propelled onto a surface with liquid, or as dry sponge to absorb liquid.
Montmorillomite, a typical clay material used as a rapid drying high temperature calcined material which is inexpensive and harder in water than most clays, reduces dusting but otherwise does not work satisfactorily in the intended use because it does not form a satisfactory re-usable granule.
The invention using garnet and/or Wollastonite (calcium metasilicate) with or without iron aluminum silicate (Staurolite) produced less dust than any of the other materials. After use of the above gypsum materials, dust from the mineral was produced over equipment and users. Use of the Wollastonite material of the invention produced negligible or little dust from release of mineral fragments in comparison. No dust was produced in a stationary air area greater than about 20 feet from the target. Thus the invention is considerably more user-friendly than any material tested above or in the prior art. In comparison asbestos material can produce minute dust particles which remain in the air for hours. The invention granules have weight so that they settle to the ground and produce little if any dust. Any substantial dust formation must then be produced by the material being blasted by the granules.
Applicants search for a material to aid in binding and to ensure the phibral strength upon impingement without fracture, has led to a series of experiments with Wollastonite. Various degrees of silane treatments have been evaluated vs volume of Wollastonite (aqueous). In one experiment, 100 grams of granulated product was vigorously mixed with 500 grams of water and tested. The above mixture was then filtered through a conical filter and the effluent was tested for solids content. It was found that Silane treated Wollastonite and Staurolite were significantly better than gypsums. However, success in the lab was not replicated during a machine test of the product during which the product broke down, dusted and flowed poorly through the blasting equipment because it plugged the nozzle and bridged the feed system for the product.
However, further work using Wollastonite showed an improved product when latex was eliminated from the formulation.
Carr in U.S. Pat. No. 4,731,125 shows a cleaning material from which contaminants cannot be removed so that the material in Carr is not reusable.
The object of the invention is to provide complexed and/or polymeric compounds containing bound minerals such as but not limited to garnet, Wollastonite, Staurolite and water-foamable polymeric material which avoid the excessive dust problem and breakdown problems of the prior art and can be recycled for further use. Cleaning of the particles of the invention allows this media to be reused and facilitates concentration of the contaminants for efficient disposal in a reduced volume. Ser. No. 376,764 discloses in general employing a pliant medium or light mineral essentially free from dust and discusses use of particulate media and reduction of the contaminated liquid; such as foam pretreated with a dry powder to increase density and abrasiveness. Specific media are herein disclosed.
It is also one of the objects of the present invention to overcome the aforementioned problems of cleaning media to provide a media capable of performing in the aforementioned desirable manner.
It is an object of the invention to provide a variety of compositions to clean hard or soft substrates and dislodge and/or remove objectionable soils. It is another object for the compositions to be capable of being propelled through the air to impact the substrate without harm thereto. Ser. No. 606,169 disclosed gypsum and Wollastonite compositions. Improved compositions of Wollastonite are herein disclosed.
It is another object of the invention to contain through absorption the soil or dust removed onto the composition and allow removal of the soil or dust in order to reuse or recycle the composition.
It is a further object to provide improved methods of polishing or cleaning hard or soft substrates by removal of objectionable soil (such as softened lead paint) and incinerating entire spent material. It is a further object not to leave any or minimal residue on a substrate or in the air.